On the Use of Rotating-Disk Geometry for Evaluating the Drag-Reducing Efficiency of Polymeric and Surfactant Additives (original) (raw)
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This paper focuses on the determination of the interaction between polymer (Polyacrylamide (PAM)) and surfactant (Sodium dod benzene sulfonate (SDBS)) as a drag reducer using Rotating Disk apparatus (RDA) at various concentrations (500, 700, 1000, 1500 and 2000) ppm individually and in the combined form under turbulent conditions at different rotation speed up to 3000 rpm, as well as studying their mechanisms as a drag reducer. The results show that the maximum percent drag reduction increases to (40, 41, 43, 45 and 48)% by using the combined additives of surfactant and polymer at the above concentrations respectively, with slower degradation and display drag reduction for a larger range of Reynolds numbers. The nano and micro particles formed from the combined PAA and SDBSA was studied using cryo-transmission electron microscopy (cryo-TEM) techniques. The images show the surrounding of polymer chain to the surfactant micelle to form an aggregate structure. A hexagonal crystalline form was suggested to describe the shape of the aggregate structure.
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Europhysics Letters (EPL), 2006
Yz -Drag reduction. PACS. 82.70.Uv -Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions). PACS. 83.50.Rp -Wall slip and apparent slip.
JAFM-On the Use of Rotating-Disk Geometry for Evaluating the
In this study we will examine the applicability of the flow induced by a rotating disk in evaluating the performance of polymeric and surfactant additives in reducing skin friction drag and effect of viscosity on drag reduction capability of polymeric and surfactant solutions. It is shown that these additives can dramatically reduce friction drag provided that the flow is occurring under turbulent conditions while they have no effect on Taylor instabilities. Based on the experimental data, a drag reduction in the range of 10% can be achieved with the effect becoming more pronounced the higher the Reynolds number.
Drag reduction in turbulent pipeline flow of mixed nonionic polymer and cationic surfactant systems
The Canadian Journal of Chemical Engineering, 2013
Turbulent drag reduction behaviour of a mixed nonionic polymer/cationic surfactant system was studied in a pipeline flow loop to explore the synergistic effects of polymeric and surfactant drag reducing additives. The nonionic polymer used was polyethylene oxide (PEO) at three different concentrations (500, 1000, and 2000 ppm). The surfactant used was cationic octadecyltrimethylammonium chloride (OTAC) at concentration levels of 1000 and 2500 ppm. Sodium salicylate (NaSal) was used as a counter-ion for the surfactant at a molar ratio of 2 (MR = Salt/OTAC = 2). Relative viscosity and surface tension were measured for different combinations of PEO and OTAC. While the relative viscosities demonstrated a week interaction between the polymer and the surfactant, the surface tension measurements exhibited negligible interaction. The pipeline results show a considerable synergistic effect, that is, the mixed polymer-surfactant system gives a significantly higher drag reduction (lower friction factors) as compared with pure polymer or pure surfactant. The addition of surfactant to the polymer always enhances drag reduction. However, the synergistic effect in mixed system is stronger at low polymer concentrations and high surfactant concentrations.
Asymptotes of maximum friction and heat transfer reductions for drag-reducing surfactant solutions
International Journal of Heat and Mass Transfer, 2001
A new maximum drag reduction asymptote (MDRA) for surfactant solutions is presented. Various concentrations including cationic and non-ionic surfactant solutions were used to experimentally determine this asymptote. It is shown that if solvent viscosity is used to compute Reynolds and Prandtl numbers for viscous solutions, it leads to underestimations of the friction coecient. To avoid uncertainties in the selection of the¯uids viscosity, most solutions used were intentionally conditioned so their shear viscosity was water-like in the ranges covered. Using the same solutions, a maximum heat transfer reduction asymptote (MHTRA) was also determined ± a correlation that did not exist for surfactants until now. Finally, by using slightly modi®ed de®nitions to quantify the heat transfer and drag reductions (TRH and TRD), it is possible to express the ratio between the MHTRA and MDRA with a constant value of 1.06, independent of Reynolds number. This relationship can be used as an auxiliary criterion to determine whether or not a solution is asymptotic when there is an uncertainty about the shear viscosity. Ó : S 0 0 1 7 -9 3 1 0 ( 0 0 ) 0 0 3 1 9 -7
Macromolecular Symposia, 2006
This work describes a method to evaluate, in reduced scale, the performance of polymer samples as drag reduction agents in aqueous solutions. To measure the pressure drop in a turbulent regime, a specially adapted capillary viscosimeter was used, with reduced dimensions adapted to produce the desired regime and adequate pressure measurement points. To verify the technique's reliability, samples of polyacrylamide were synthesized with different molar masses, by varying the quantity of the polymerization initiator. The molar masses obtained were determined by size exclusion chromatography (SEC). The efficiency of the polymer as a drag reducer, as expected, increased as the molar mass increased, which validates the use of this method to study the drag reduction properties of polymer materials in aqueous solutions.
Drag reduction by polymer additives from turbulent spectra
Physical Review E, 2010
We extend the analysis of the friction factor for turbulent pipe flow reported by G. Gioia and P. Chakraborty (G. Gioia and P. Chakraborty, Phys. Rev. Lett. 96, 044502 (2006)) to the case where drag is reduced by polymer additives. * calzetta@df.uba.ar
Reviews on drag reducing polymers
Korean Journal of Chemical Engineering, 2015
Polymers are effective drag reducers owing to their ability to suppress the formation of turbulent eddies at low concentrations. Existing drag reduction methods can be generally classified into additive and non-additive techniques. The polymer additive based method is categorized under additive techniques. Other drag reducing additives are fibers and surfactants. Non-additive techniques are associated with the applications of different types of surfaces: riblets, dimples, oscillating walls, compliant surfaces and microbubbles. This review focuses on experimental and computational fluid dynamics (CFD) modeling studies on polymer-induced drag reduction in turbulent regimes. Other drag reduction methods are briefly addressed and compared to polymer-induced drag reduction. This paper also reports on the effects of polymer additives on the heat transfer performances in laminar regime. Knowledge gaps and potential research areas are identified. It is envisaged that polymer additives may be a promising solution in addressing the current limitations of nanofluid heat transfer applications.